Forecasting the impact of means restriction on the suicide mortality rate in the Region of the Americas: an ecological modeling study

Summary Background The suicide mortality rate has been increasing in Region of the Americas, despite decreasing in all other World Health Organization (WHO) regions. Means restriction is an effective evidence-based intervention for suicide prevention. The objective of the current study was to estimate the impact of implementing national-level means restriction policies (i.e., firearm and pesticide restrictions) on the suicide mortality rate in the Region of the Americas. Methods In this ecological modeling study, two counterfactual scenarios were investigated using sex-specific suicide mortality data from the WHO Global Health Estimates database for 2000 to 2019. Forecasted sex-specific age-standardized suicide mortality rates were then estimated for each country for 2020 to 2030. Counterfactual scenario 1 involved modeling the impact of a firearm or pesticide restriction implemented in 2020 for those countries where the respective means accounted for 40% or more of all suicides for at least one sex in 2019, while in counterfactual scenario 2 this threshold was reduced to 20% or more. Findings It was estimated that if a firearm or pesticide restriction had been implemented in 2020 in those countries where the respective means accounted for 40% or more of all suicides for at least one sex in 2019, by 2030 the male and female suicide mortality rate in the Region of the Americas would be 20.5% (from 14.5 [95% Confidence Interval [CI]: 14.1, 15.0] per 100,000 males to 11.5 [95% CI: 11.1, 12.0] per 100,000 males) and 11.1% (from 4.5 [95% CI: 4.4, 4.7] per 100,000 females to 4.0 [95% CI: 3.9, 4.2] per 100,000 females) lower than the rate if no such restrictions were implemented, respectively. When the threshold was reduced to 20% or more, minimal additional gains in terms of number of suicides avoided and suicide mortality rate reduction would be achieved. Interpretation The implementation of a firearm or pesticide restriction policy in countries where the respective means account for a large proportion of suicides (e.g., at least 40%) could aid the Region of the Americas in achieving the WHO target of a one third reduction in the suicide mortality rate by 2030. Funding This work received no funding.


Supplementary Table
. Predicted age-standardized suicide mortality rate per 100,000 population and number of avoided deaths by suicide in seven countries in the Region of the Americas under a counterfactual scenario of a pesticide or firearm restriction implemented in 2020 for the years 2021

Andean Area
Central America, Mexico and Latin Caribbean North America Non-Latin Caribbean

Southern Cone
Region of the Americas

Andean Area
Bolivia Colombia Peru Ecuador Venezuela      APC: Average annual percent change; APC: Annual percent change; CI: Confidence interval; F: Females; M: Males; n/a: Not available a per 100,000 population b A value of 0.5 per 100,000 population was imputed for one or more years that had an estimated suicide mortality rate of zero per 100,000 population.Note.Bolded text indicates statistical significance (p<0.05).For Antigua and Barbuda, APC was not estimated for the linear segment following 2011 for males, and prior to 2011 for females as the suicide mortality rates was estimated to be zero per 100,000 population consistently during these periods.*A value of 0.5 per 100,000 population was imputed for one or more years that had an estimated suicide mortality rate of zero per 100,000 population.

Supplementary Figure 2 .
Age-standardized suicide mortality rate among females, and the trend over time in the Region of the Americas and its sub-regions, 2000-2019 Note.Diamonds indicate identified points of inflection.Statistically significant linear segments at p<0.05 are bolded.
Age-standardized suicide mortality rate among females, and the trend over time in the Andean Area sub-region and its countries, 2000-2019 Note.Diamonds indicate identified points of inflection.Statistically significant linear segments at p<0.05 are bolded.

Supplementary Figure 6 .
Age-standardized suicide mortality rate among females, and the trend over time in the Central America, Mexico and Latin Caribbean subregion and its countries, 2000-2019 Note.Diamonds indicate identified points of inflection.Statistically significant linear segments at p<0.05 are bolded.

Figure 7 .
Age-standardized suicide mortality rate among males, and the trend over time in the Non-Latin Caribbean sub-region and its countries, 2000-2019 Note.Diamonds indicate identified points of inflection.Statistically significant linear segments at p<0.05 are bolded.

Supplementary Figure 8 .
Age-standardized suicide mortality rate among females, and the trend over time in the Non-Latin Caribbean sub-region and its countries, 2000-2019 Note.Diamonds indicate identified points of inflection.Statistically significant linear segments at p<0.05 are bolded.*A value of 0.5 per 100,000 population was imputed for one or more years that had an estimated suicide mortality rate of zero per 100,000 population.
Age-standardized suicide mortality rate among females, and the trend over time in the Southern Cone sub-region and its countries, 2000-2019 Note.Diamonds indicate identified points of inflection.Statistically significant linear segments at p<0.05 are bolded.

Table 2 .
Report numbers of individuals at each stage of study-eg numbers potentially eligible, examined for eligibility, confirmed eligible, included in the study, completing follow-up, and analysed Joinpoint analysis of age-standardized suicide mortality rates (per 100,000 people) over the past 20 years in the Region of the Americas and its sub-regions APC: Average annual percent change; APC: Annual percent change; CI: Confidence interval; F: Females; M: Males a per 100,000 population Note.Bolded text indicates statistical significance (p<0.05).Supplementary Figure 1.Age-standardized suicide mortality rate among males, and the trend over time in the Region of the Americas and its sub-regions, 2000-2019 Note.Diamonds indicate identified points of inflection.Statistically significant linear segments at p<0.05 are bolded.

Table 3 .
Joinpoint analysis of age-standardized suicide mortality rates (per 100,000 people) over the past 20 years in the Andean Area sub-region, by country APC: Average annual percent change; APC: Annual percent change; CI: Confidence interval; F: Females; M: Males a per 100,000 population Note.Bolded text indicates statistical significance (p<0.05).Supplementary Figure 3. Age-standardized suicide mortality rate among males, and the trend over time in the Andean Area sub-region and its countries, 2000-2019 Note.Diamonds indicate identified points of inflection.Statistically significant linear segments at p<0.05 are bolded.

Table 4 .
Joinpoint analysis of age-standardized suicide mortality rates (per 100,000 people) over the past 20 years in the Central America, Mexico and Latin Caribbean sub-region,

3.62 -539, -1.83 2000-19 -3.62 -539, -1.83
Age-standardized suicide mortality rate among males, and the trend over time in the Central America, Mexico and Latin Caribbean sub-region and its countries, 2000-2019 Note.Diamonds indicate identified points of inflection.Statistically significant linear segments at p<0.05 are bolded.

Table 5 .
Joinpoint analysis of age-standardized suicide mortality rates (per 100,000 people) over the past 20 years in the Non-Latin Caribbean subregion, by country

Table 6 .
Joinpoint analysis of age-standardized suicide mortality rates (per 100,000 people) over the past 20 years in the North America sub-region, by country a per 100,000 population Note.Bolded text indicates statistical significance (p<0.05).Supplementary Figure 9. Age-standardized suicide mortality rate among males, and the trend over time in the North America sub-region and its countries, 2000-2019 Note.Diamonds indicate identified points of inflection.Statistically significant linear segments at p<0.05 are bolded.

Table 7 .
Joinpoint analysis of age-standardized suicide mortality rates (per 100,000 people) over the past 20 years in the Southern Cone sub-region, by country APC: Average annual percent change; APC: Annual percent change; CI: Confidence interval; F: Females; M: Males a per 100,000 population Note.Bolded text indicates statistical significance (p<0.05).Supplementary Figure 11.Age-standardized suicide mortality rate among males, and the trend over time in the Southern Cone sub-region and its countries, 2000-2019 Note.Diamonds indicate identified points of inflection.Statistically significant linear segments at p<0.05 are bolded.

Table 10 .
Model fit statistics for the forecasting models

Table 14 .
Effect estimates for a firearm ban